I did them for a while but ended up around 600lbs pretty quickly. If you're going to do them effectively they need to be heavy, but my thinking is that if I have the energy to load up the bar up to 600lbs then I obviously left something in the tank on Deadlifts. So why don't I just do more deadlifts?

Just my 2 cents, and why I stopped doing them. Nowadays deadlifts with very heavy band tension just do so much more for my traps then shrugs ever did and for lifters they're far more lift specific. So I'm sticking with them.

If we're talking rearward shrugs, scapulae/kelso shrugs then I'm all for them. They serve a specific purpose which isn't necessarily served by deadlifts or rows so they're useful.